备忘录模式又称快照模式，是行为模式之一；
备忘录模式的应用场景是对某些对象做出了改变之后，又需要恢复到改变之前的状态！常常和命令模式结合使用...
备忘录中的三张角色;
1、原始角色，需要具有创建备忘录和根据备忘录恢复状态的方法
/* * Copyright (c) 2017. Xiaomi.Co.Ltd All rights reserved */package com.pt.memo;/** * @description 游戏角色 * @author panteng * @date 17-2-24. */public class Player { String name; //角色名称 Integer HP; //血量 Weapon weapon; //武器 public Player(){ } public Player(String name, Integer HP, Weapon weapon){ this.name = name; this.HP = HP; this.weapon = weapon; } public Memotor createMemotor(){ //此处也并不是必须定义成final，定义成final这样可能会导致无法回收，但可以更有效的防止备忘录被修改 final Memotor memotor = new Memotor(this.HP, this.weapon); return memotor; } /** * 深复制与浅复制的使用因场景而定 * @return * @throws Exception */ public Memotor createMemotorByDeepCopy() throws Exception{ //采用深复制 final Memotor memotor = new Memotor(new Integer(this.HP), (Weapon) this.weapon.deepClone()); return memotor; } public void recover(Memotor memotor){ this.HP = memotor.getHP(); this.weapon = memotor.getWeapon(); } public String getName(){ return name; } public void setName(String name){ this.name = name; } public Integer getHP(){ return HP; } public void setHP(Integer HP){ this.HP = HP; } public Weapon getWeapon(){ return weapon; } public void setWeapon(Weapon weapon){ this.weapon = weapon; } public void showState(){ System.out.println(this.name + " HP:" + this.HP + " weapon:" + weapon); }} 武器类
/* * Copyright (c) 2017. Xiaomi.Co.Ltd All rights reserved */package com.pt.memo;import com.pt.prototype.PrototypeModle;/** * @description 武器类 * @author panteng * @date 17-2-24. */public class Weapon extends PrototypeModle { String name; //武器名称 Float attackDistance; //攻击距离 Float ATK; //攻击力 public Weapon(){ } public Weapon(String name, Float attackDistance, Float ATK){ this.name = name; this.attackDistance = attackDistance; this.ATK = ATK; } public String getName(){ return name; } public void setName(String name){ this.name = name; } public Float getAttackDistance(){ return attackDistance; } public void setAttackDistance(Float attackDistance){ this.attackDistance = attackDistance; } public Float getATK(){ return ATK; } public void setATK(Float ATK){ this.ATK = ATK; } /** * Returns a string representation of the object. In general, the * { @code toString} method returns a string that * "textually represents" this object. The result should * be a concise but informative representation that is easy for a * person to read. * It is recommended that all subclasses override this method. * * The {
@code toString} method for class { @code Object} * returns a string consisting of the name of the class of which the * object is an instance, the at-sign character `{ @code @}', and * the unsigned hexadecimal representation of the hash code of the * object. In other words, this method returns a string equal to the * value of: * * * getClass().getName() + '@' + Integer.toHexString(hashCode()) *
* * @return a string representation of the object. */ @Override public String toString(){ return super.toString() + " name:" + this.name + " ATK:" + this.ATK + " attackDistance:" + attackDistance; }} 2、备忘录角色，用于保存原始角色需要记录的状态信息
/* * Copyright (c) 2017. Xiaomi.Co.Ltd All rights reserved */package com.pt.memo;/** * @description 游戏者备忘录 * @author panteng * @date 17-2-24. */public class Memotor { public Integer HP; public Weapon weapon; public Memotor(){ } public Memotor(Integer HP, Weapon weapon){ this.HP = HP; this.weapon = weapon; } public Integer getHP(){ return HP; } public void setHP(Integer HP){ this.HP = HP; } public Weapon getWeapon(){ return weapon; } public void setWeapon(Weapon weapon){ this.weapon = weapon; }} 3、备忘录管理者角色，主要做好封装，防止备忘录被修改
/* * Copyright (c) 2017. panteng.Co.Ltd All rights reserved */package com.pt.memo;/** * @description 备忘录管理者，之所以有此角色，是保护备忘录不被改变，备忘录模式使用上，除管理者和发起者外，其他不可以操作备忘录； * @author panteng * @date 17-2-24. */public class MemotorManager { Memotor memotor; public MemotorManager(Memotor memotor){ this.memotor = memotor; } public Memotor getMemotor(){ return memotor; } public void setMemotor(Memotor memotor){ this.memotor = memotor; }} 4、测试类
/* * Copyright (c) 2017. Xiaomi.Co.Ltd All rights reserved */package com.pt.memo;import org.junit.Test;/** * @description * @author panteng * @date 17-2-24. */public class MemotorTest { @Test public void memotoeTest() throws Exception{ //创建一个两个武器 Weapon weapon1 = new Weapon("手枪", 200.1F, 100.5F); Weapon weapon2 = new Weapon("狙击枪", 1000.25F, 200.5F); //创建一个游戏角色 Player player = new Player("魂斗罗", 1000, weapon1); player.showState(); //战斗前先备份 MemotorManager memotorManager = new MemotorManager(player.createMemotor()); MemotorManager memotorManager1 = new MemotorManager(player.createMemotorByDeepCopy()); System.out.println("战斗... ... 切换武器... ..."); player.setWeapon(weapon2); //切换武器 player.setHP(0); //挂了 player.showState(); //恢复 System.out.println("恢复战斗前的状态... ..."); player.recover(memotorManager.getMemotor()); player.showState(); //假如战斗过程中角色发生了这样的变化 System.out.println("=========================================================="); player.setHP(1); player.getWeapon().setATK(0F); player.getWeapon().setAttackDistance(0F); player.showState(); player.recover(memotorManager.getMemotor()); player.showState(); //武器无法恢复，因为备份过程中采用的是浅复制，血量恢复了，说明Integer采用的是深复制 //使用第二种方式恢复 player.recover(memotorManager1.getMemotor()); player.showState(); }}
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